JPH0733367B2 - Process for producing N- (2-chloro-4-nitrophenyl) -3-trifluoromethylbenzenesulfonamide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention provides novel N- (2-chloro-4-nitrophenyl) -3-trifluoromethylbezene sulfonamides represented by the formula (II). [In the formula, X and Y each represent a hydrogen atom or a chlorine atom. ] The manufacturing method of.

More specifically, the formula (I) [In the formula, X and Y are the same as X and Y in the formula (II). ] N- (2-chlorophenyl) -3-trifluoromethylbenzenesulfonamide represented by
It relates to a method of obtaining a compound of formula (II).

The benzene compound having a sulfonamide structure is a useful compound that has been conventionally known as a pesticide such as a fungicide.

[Prior Art] JP-A-58-219159 discloses the following formula [In the formula, R ₁ and R ₂ each represent a hydrogen atom or a methyl group, X represents a methyl group, a halogen atom, or a nitro group, and n represents an integer of 1 to 3. Provided that R ₁ is a methyl group, R ₂ is a hydrogen atom, X is a compound represented by a 2-chloro-4-nitro group, and R ₁ and R ₂ are simultaneously a hydrogen atom and X is 4
Excludes compounds that are -chloro and 3,4-dichloro. ] A 3-nitrobenzenesulfonamide compound represented by the following formula has been proposed, and it is described that this compound has a bactericidal effect.

Further, the same applicant as the present invention is disclosed in the above-mentioned JP-A-58-219159.
The N- (2-chloro-4-nitrophenyl) -3-trifluoromethylbenzenesulfonamide compound represented by the formula (II), which is a compound having a greater bactericidal activity than the compound disclosed in JP-A No. Heading filed (Japanese Patent Application No. 60-36532).

[Problems to be solved by the invention]

The present inventors diligently studied the advantageous method for establishing the industrial production method of the compound of the formula (II).

In the above-mentioned JP-A-58-219159, for example, N- (2-chloro-5-nitrophenyl) -3-nitro-4-methylbenzenesulfonamide is used. In order to obtain the above compound, 2-chloro-5-nitroaniline and an equimolar amount of 3-nitro-4-methylbenzenesulfonyl chloride were stirred under reflux in the presence of an equimolar amount of pyridine in a toluene solvent. There is a description to carry out the condensation reaction.

However, the yield of the desired product is at most 50%, and even when the method is applied to the method for producing the compound of the formula (II) according to the present invention, the desired product can be obtained only in almost the same yield. I couldn't.

Thus, one of the reasons why the target product is not obtained in high yield is presumed to be the use of anilines having a nitro group on one side of the substrate for the condensation reaction.

In fact, according to the studies by the present inventors, for example, 3-trifluoromethyl-4-chlorobenzenesulfonyl chloride was selected as one of the reaction substrates, and 2-chloro-4-nitroaniline and 2-chloroaniline were respectively added thereto. When the condensation reaction was carried out, the yield of the condensation reaction product was about 10%, and it was found that it is more advantageous to use the latter, which is not nuclear-substituted by the nitro group, for the reaction.

In addition, when 2-chloro-4-nitroaniline is used, its production is usually dichlorobenzene as a starting material,
Since the process of nitration and ammonolysis of this is long, it is expensive and it is difficult to obtain a high-purity product, which is also disadvantageous as a raw material.

The object of the present invention is to solve these problems, to provide a compound of formula (II) at low cost and in high yield. [In the formula, X and Y are the same as X and Y in the formula (I). ] It is providing the method of manufacturing.

[Means for solving problems]

Based on the above-mentioned problems, an intensive study was conducted, and inexpensive 2-chloroanilines were selected as one of the reaction substrates of the target product of the present invention, whereby a compound of formula (I) was obtained in a high yield, and subsequently specified. It was found that by nitrating the compound of formula (I) under the nitration reaction condition (1), the desired product of formula (II) compound can be obtained by an industrially advantageous method.

That is, when the compound of formula (I) was nitrated under specific conditions, it was found that the nitro group can be introduced almost selectively only at the 4-position with respect to the anilide group, which is suitable for the present invention.

That is, the present invention has the formula (I) [In the formula, X and Y each represent a hydrogen atom or a chlorine atom. ] N- (2-chlorophenyl) -3-trifluoromethylbenzenesulfonamide represented by the following formula, in the presence or absence of concentrated sulfuric acid, relative to 1 part by weight of the compound of the formula (I).
The nitration reaction is carried out at a temperature of 10 to 120 ° C in 05 to 10 parts by weight of glacial acetic acid or 0.01 to 2 parts by weight of acetic anhydride to obtain the compound of formula (II) [In the formula, X and Y are the same as X and Y in the formula (I). ] N- (2-chloro-4-nitrophenyl)-
It is a production method for obtaining 3-trifluoromethylbenzenesulfonamide.

In the method of the present invention, it can be produced from the compound of formula (I),
The corresponding formula (II) compound, which is a nitro compound, is N
-(2-chloro-4-nitrophenyl) -3-trifluoromethylbenzenesulfonamide, N- (2-chloro-4-nitrophenyl) -3-trifluoromethyl-4
-Chlorobenzenesulfonamide, N- (2-chloro-
4-nitrophenyl) -2-chloro-5-trifluoromethylbenzenesulfonamide, N- (2-chloro-4
-Nitrophenyl) -2,4-dichloro-5-trifluoromethylbenzesulfonamide and the like.

Further, the compound of formula (I) used in the present invention can be easily obtained in a high yield by condensation of the corresponding benzenesulfonyl chlorides and 2-chloroaniline.

The benzenesulfonyl chlorides include, for example, 3-trifluoromethyl-4-chlorobenzenesulfonyl chloride, As described above, it can be obtained by reacting O-trifluoromethylchlorobenzene with chlorosulfonic acid.
Chloroanilines are known compounds and are easily available at a low price.

The present invention is carried out as follows.

Usually, 0.9 to 2 mol, preferably 1.0 to 1.3 mol of nitric acid and 1 weight of the compound of formula (I) are used per 1 mol of the compound of formula (I) of N- (2-chlorophenyl) -3-trifluoromethylbenzenesulfonamide. The nitration reaction is carried out using 0.01 to 2 parts by weight, preferably 0.05 to 1 part by weight of acetic anhydride, or 0.05 to 10 parts by weight, and preferably 0.05 to 5 parts by weight of glacial acetic acid per part.

The use of multiple sulfuric acids, which are used as mixed acids in conventional nitration reactions, is not preferred in the process of the invention because of the increase in by-products. Since the reaction is slow when using only nitric acid, sulfuric acid may be allowed to coexist with acetic anhydride or glacial acetic acid. In that case, it is preferable to use 0.1 part by weight or less based on the compound of the formula (I). Also, if the amount of acetic anhydride or glacial acetic acid used is out of these ranges, the reaction will be delayed and the production of by-products such as isomers and dinitro compounds will increase, and the yield of the target compound of formula (II) will be increased. The rate tends to decrease.

In the method of the present invention, the solvent may or may not be used, but when a solvent is used, 1,1,2
-Trichloroethane, 1,2-dichloroethane, carbon tetrachloride and the like can be exemplified. The amount used is preferably 2 to 10 parts by weight with respect to 1 part by weight of the compound of formula (I).

In the nitration reaction, the compound of formula (I), a solvent and acetic anhydride or glacial acetic acid, and further sulfuric acid if necessary, are placed in a reaction vessel and heated to 10 to 120 ° C., preferably 60 to 100 ° C. to form nitric acid. Is usually added dropwise over 1 to 2 hours, and then the reaction is terminated by further stirring for 0.5 to 10 hours. When the reaction temperature is out of this range, by-products tend to increase.

After the reaction, for example, the following method is used.

Water is added to the residue obtained by distilling off the solvent from the reaction solution under reduced pressure, and the precipitated crystals are filtered and dried to obtain the desired product (II) compound. If necessary, this is subjected to column chromatography or recrystallization.

Thus, according to the method of the present invention, a nitro group is selectively introduced only at the 4-position with respect to the anilide group of the compound of formula (I), and N- (2-chloro-4-nitrophenyl) -3-
Trifluoromethylbenzene sulfonamides can be obtained.

In the present invention, the compound of formula (I) used as a starting material is benzenesulfonyl chloride and 2-chloroaniline in the presence of an organic basic catalyst according to the method described in JP-A-58-219159. It suffices to carry out a condensation reaction of the compounds.

Alternatively, the present inventors separately found a condensation reaction between benzenesulfonyl chlorides and 2-chloroanilines,
By using the method of patent application, that is, in the presence of a basic catalyst, if necessary, in the coexistence of a solvent such as xylene or O-dichlorobenzene, the reaction temperature of 130 to 200 ° C. is maintained and an inert gas is generated. It can be produced more efficiently by a method of reacting while blowing it into the reaction system.

〔Example〕

 Hereinafter, the present invention will be described in more detail with reference to examples.

Synthesis Example Synthesis of N- (2-chlorophenyl) -3-trifluoromethyl-4-chlorobenzenesulfonamide A 500 ml four-necked flask was charged with 2-chloroaniline 25.5 g, pyridine 15.8 g as a basic catalyst, and toluene 150 ml. ,
The temperature was raised to 110 ° C., and 55.8 g of 3-trifluoromethyl-4-chlorobenzenesulfonyl chloride dissolved in 50 ml of toluene was added dropwise with stirring at 100 to 110 ° C. over 1 hour. Continue to stir at the same temperature for 4 hours,
The reaction was completed. The reaction solution was cooled to room temperature, 200 ml of 5% hydrochloric acid water was added, and the mixture was stirred for 30 minutes to separate the layers.

The obtained organic layer was washed 3 times with 100 ml of water, then toluene was distilled off under reduced pressure, the obtained residue was washed with benzene, filtered under reduced pressure and dried to obtain N- (2- 67.5 g (yield 91.2%) of chlorophenyl) -3-trifluoromethyl-4-chlorobenzenesulfonamide was obtained.

The reaction temperature was maintained at 130 ° C, and nitrogen was added to the reaction solution at 50 ml /
95% yield when carried out while blowing at a flow rate of minutes
Met.

Example-1 Synthesis of N- (2-chloro-4-nitrophenyl) -3-trifluoromethyl-4-chlorobenzenesulfonamide N- (2-chlorophenyl) -3-trifluoromethyl-4-chlorobenzenesulfonamide 18.5 Charge 50 g of glacial acetic acid and 1.0 g of concentrated sulfuric acid into a 100 ml four-necked flask, and
While stirring at 5 ° C., 3.5 g of fuming nitric acid was mixed with 10 ml of glacial acetic acid, and this was added dropwise over 1 hour. In addition, 2 at 100 ℃
Stirring was carried out for a period of time to complete the reaction. After cooling, the reaction mixture was discharged into 100 g of crushed ice, the precipitated crystals were collected by filtration, washed with 50 ml of methanol, and dried to give a melting point of 169.5.
18.3 g of N- (2-chloro-4-nitrophenyl) -3-trifluoromethyl-4-chlorobenzesulfonamide having a purity of 99.75% (GC internal standard analysis) having a temperature of -171.5 ° C.
(Yield 88.9%) was obtained.

Example-2 Synthesis of N- (2-chloro-4-nitrophenyl) -2-chloro-5-trifluoromethylbenzenesulfonamide In the synthesis example, instead of 3-trifluoromethyl-4-chlorobenzenesulfonyl chloride, 2-chloro-
N- (2-chlorophenyl) -2-chloro-5-trifluoromethylbenzenesulfonamide (18.5 g), acetic anhydride (1.0 g) and a solvent were obtained in exactly the same manner except that 5-trifluoromethylbenzenesulfonyl chloride was used.
Charge 50 ml of 1,1,2-trichloroethane to a 200-ml four-necked flask, raise the temperature to 95 ° C, and stir for 3.5 hours with 3.5 g of fuming nitric acid dissolved in 15 ml of 1,1,2-trichloroethane.
Dropwise charge at 94-96 ° C. Subsequently, the mixture was kept at the same temperature for 2 hours while stirring to terminate the reaction, and cooled to room temperature.
The solvent of the obtained reaction mixture was distilled off under reduced pressure, the residue was washed with 100 ml of water, and then collected by filtration. 50 ml of crude crystals
After washing with N and dried, 17.5 g (yield 84.3%) of N- (2-chloro-4-nitrophenyl) -2-chloro-5-trifluoromethylbenzenesulfonamide (melting point 157.5-158.5 ° C) is obtained. It was

Example-3 Synthesis of N- (2-chloro-4-nitrophenyl) -3-trifluoromethylbenzenesulfonamide N- (2-chlorophenyl) -3-trifluoromethylbenzenesulfonamide 16.8 g, catalytic acetic anhydride 0.3g,
A mixture of 40 ml of 1,1,2-trichloroethane was heated to 95 ° C, and a solution of 10 ml of 1,1,2-trichloroethane containing 3.5 g of 98% nitric acid was added dropwise at the same temperature over 1 hour. Then 90
The reaction was completed by stirring while keeping the temperature at ~ 95 ° C for 1 hour. After cooling the reaction solution, the solvent was distilled off under reduced pressure, and the residue was poured into 100 ml of water to crystallize and filtered off.

The crystals were washed with 100 ml of water, dried and then recrystallized with 40 ml of methanol to give 13.2 g of N- (2-chloro-4-nitrophenyl) -3-trifluoromethylbenzenesulfonamide (melting point: 126-127 ° C). (Yield 69.3%) was obtained.

Reference Example In a 400 ml flask, 200 ml of O-dichlorobenzene, 1 ml of pyridine and 1.7 g of 2-chloro-4-nitroaniline (0.0
1 mol) was charged, and 2.5 g (0.01 mol) of 3-trifluoromethylbenzenesulfonyl chloride was added dropwise with stirring over 30 minutes at room temperature. Then, heat and reflux (175
The reaction was completed by stirring at ~ 180 ° C) for 10 hours. After cooling to room temperature, the reaction solution was thoroughly washed with diluted hydrochloric acid and then with water, dehydrated with anhydrous sodium sulfate, and then O-dichlorobenzene was distilled off under reduced pressure. The residue was purified according to Example-3,
N- (2-chloro-4-nitrophenyl) -3-trifluoromethylbenzenesulfonamide 1.9 g (yield 50%)
Got

Claims (3)

[Claims] 1. A formula (I) [In the formula, X and Y each represent a hydrogen atom or a chlorine atom. ] N- (2-chlorophenyl) -3-trifluoromethylbenzenesulfonamide represented by the formula (1) is used in the presence or absence of concentrated sulfuric acid in an amount of 0.01 relative to 1 part by weight of the compound of the formula (I).
The formula (II) is used to carry out the nitration reaction in 10 to 120 ° C. in ˜2 parts by weight of acetic anhydride. [In the formula, X and Y are the same as X and Y in the formula (I). ] N- (2-chloro-4-nitrophenyl)-
A method for producing 3-trifluoromethylbenzenesulfonamide. 2. Formula (I) [In the formula, X and Y each represent a hydrogen atom or a chlorine atom. ] N- (2-chlorophenyl) -3-trifluoromethylbenzenesulfonamide represented by the following formula is used in the presence or absence of concentrated sulfuric acid in an amount of 0.05 with respect to 1 part by weight of the compound of the formula (I).
The formula (II) is used to perform the nitration reaction in 10 to 120 parts by weight of glacial acetic acid at 10 to 120 ° C. [In the formula, X and Y are the same as X and Y in the formula (I). ] N- (2-chloro-4-nitrophenyl)-
A method for producing 3-trifluoromethylbenzenesulfonamide. 3. The method according to claim 1 or 2, wherein the concentrated sulfuric acid is present in an amount of 0 to 0.1 part by weight per 1 part by weight of the compound of the formula (I).